Butterfish
Otolith description
The general shape of the otolith is ovally pointed. The sulcus runs straight over of the total length of the otolith, slightly pointing down at the posterior end. The sulcus is deep and open at the ostium. Ostium and cauda are clearly separated. The ostium is deeper and wider than the cauda. The surface of the inside and outside is smooth. The margins are smooth. The dorsal and posterior margins are rounded, while the ventral margin is straight or just slightly rounded. The rostrum is well-developed and pointed. The antirostrum is visible and rounded. The inside is flat, but the ventral part is thicker than the dorsal part. The outside is slightly concave. The otolith is thick. Otoliths do not exceed 2.5 mm in length.
When eroded the ostium remains visible. The rostrum is rounded.
Eroded otoliths of butterfish can be difficult to distinguish from those of eelpout Zoarces viviparus. The rostrum of butterfish otoliths is less well-developed, but the sulcus is deeper than in eelpout otoliths. The otolith length-width ratio is smaller in butterfish otoliths. Otoliths of butterfish are thicker, but smaller than eelpout otoliths. Otoliths > 2.5 mm are always of eelpout.
Otoliths of juvenile butterfish already have the ovally pointed shape. The sulcus is slightly visible. The rostrum is already distinct and slightly pointed.
Fish length and distribution
Butterfish can grow up to 25 cm. Butterfish is a bottom-living fish (PHOLGUNN.TIF) found in coastal waters, also in the tidal zone. It is found among rocks and algae. Spawning takes place in January and February (Wheeler, 1978, Nijssen and De Groot, 1987, Witte et al., 1991, Knijn et al., 1993, Muus et al., 1999).
Butterfish is a common fish found in the coastal waters of the Northern Atlantic, North Sea and Baltic.
Sample origin
Western Wadden Sea.